Switch interlock



1,482,051 H. F. TURNER SWITCH INTERLOCK Filed Jan. 2. 1920 4 2 Sheets-Sheet 1 Jan. 29 1924.

TLA/MAM cui? Jan. 29 1924.

H' F TURNER SWITCH INTERLOCK Filed Jan. 2I 1920 fnzenoiw' WAM Tv Patented Jan. 29, 1924.

UNITED STATES PATENT OFFICE.

HERBERT F. TURNER, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO SEARS B. CON- DIT, JR., OF BOSTON, MASSACHUSETTS.

SWITCH INTERLOCK.

Application illcd January 2, 1920. Serial No. 348,866.

To all whom t may concern:

Be it known that l, Hnncmrr F. TURNER, a subject of the Kingr of Great Britain. residing,r at Cambridge, in the county of Suffolk I and State of Massachusetts, have invented an Improvement in Switch lnterloclcs, of which the following is a specification.

In the supply of power for many purposes, such as certain manufacturing processes, lighting` and so forth, it is essential that the supply is not interrupted, or suffers but momentary interruption due to the failure of generating apparatus, or from some other unforeseen happening.

To insure substantial continunity of service, it is common to employ a plurality of sources of power any one of which may be connected tothe power 'supply circuit upon failure of one'o'f'the power sources thereby to guard against; a protracted 'intermption of power in the circuit. y Usually two independent sources 'of power which may be remote from each other'are adaptedto be lindependently connected to thepower supply circuit through separate switches, one of which must4 always be open so that but one power source at a time is connected` to the circuit, the other being connectedonly upon ari-emergency. i v

It 'fre uentlyA happens, however, that,Y through t e ncarelessness or ignorance of a station attendant, the switch 4controlling! one power source is thrown in while the other power source is connected to the circuit. The usual result is the opening of circuit breakers throughout the system, if not a more extended damage, and, in addition, there is usually a long and serious delay before the error can be rectified and power again restored'to, the circuit. The usual method of preventing the closing of the wrong switch is by placing a wooden block in the switcli mechanism:or tying a red tagr on the switch handle; but this method is not effective for the block will fall out or be removed and the ta.' is ignored.

The 'object of my invention is the rovision of an interlock between the switches controllingr the connection of the plurality of sources of power to the power supply circuit, whereby when the interlock is set in one position one switch is free to be. operated While the other switch is positively locked against operation; and whenthe interlock is moved to anotherposition the Switch will be positively locked against operation and the second switch will be free to hc operated. l may also so arrange the interlock that in a certain position thereof both switches will be locked against operation.

The means whereby l accomplish this result comprises a holt extended between thc operating mechanism of the switches so constructed and arranged that when moved in one position it positively engages the mechanism of one switch to restrain that switch from operation and is freed from engagement with the mechanism ot the other `switch to permit the operation of that switch. When moved in the reverse direction it is arranged to lock the first named switch and release the lock onthe second switch. When placedin a middle or neutral position it may engage the mechanism of all switches thereby to restrain all switches from operation.

A further object of my invention is to arrange the interlock as an attachment to apply to existingr switches for the purpose above set4 forth.

A further object of my invention is to prov vide a Single switch with a lock bywhich the switch may be locked against operation and may be unlocked for operation only by the one having the proper key. Y

A yet further object of my invention is the provision of the interlock with means by which it maybe positively locked in any position thereby positively to lock the switches Yfor or against operation as deterrninedE by the setting of the interlock.

Fig. 1 is a front view of two switches with which my invention is associated.

Fig. 2 is a plan view of Fig. 1.

Fig. 3 is a side view of one of the switches with the interlock in section, taken alongr line 3-'3 of Fig. 2.v

Fig. 4 is a plan section through the witches and interlock along' lines 4-4 of F ig. 5 is a detail showing the interlock holding and locking means.

Fig. 6 is a modiiied form of interlock having no neutral'position and arranged always to lock or release one switch.

Fig. 7 is a. side view of the interlock supporting block.

Fig. 8 is a detail of the lock as applied t0 a single switch. A As here shown my invention `is -applied to the switch mechanisms or switch face plates mounted side by side on the switch hoard 10. l'lach face plate 11 and ll"` has the slot l2 and 12" therein through which the parallel spaced-apart switch rods 13 and 13a extend which are pivotally connected to the operatV ing handles 14 and 14, pivoted to the face plates at 15 and 15. The switches are locked in closed position by the latches 16 and 1G engaging pins 1T and 17a and the switches are automatically tripped b v the tripping coils 18 and 18'L The switches may also be manually opened -by depressing said pins,17 and 1T, as is common practice.

A block 2O having a centra-l opening 2l into which the slot 22 extends from one side thereof is mounted on the inner side of each face plate'and the tube 23 extends between said blocks and has its end received and frictionally retained in the openings therein. Said blocks are secured to said face plates by the bolts'QA extended through the ends of said blocks on each side of said openings 21 therein; and the bolts extended through the slotted ends of the'blocls additionally serve to Securely clamp said tube to said blocks.

An interlocking bolt`25 is received in said tube 23 and is a Sliding fit therein. Y Said bolt, as more particularly illustrated in Fig. 2, is arranged to engage either one or the other, o r both, of said switch-mechanisms to lock one or the other,or both, of said switches against operation.` For' this purpose the-inner switch rods 13a of both switch mechanisms are-'provided with the locking 'apertures thereinV in which the ends of said bolts are adapted to `be received when the switch mechanisms are in openfposition thereby to lock the.l switchesagainst operation; With the bolt in saidapertures it is seen that the switch handles cannot-be moved and the switches are therefore, positively restrainedv in open' position.

The bolt enclosing tube or easingkl is formed with an opening or slotl 40 therein intermediate its ends and said bolt 2'5V is provided 'witha knob'or handle 41' by which the bolt may be manually 'operated' to lock the switch. Said slot 40,l as in Fig. 1,*m'ay be provided with three notches as 40, 40", and 40C in which the knob or`h`andle 41 is adapted to be received to be held against unintentional movement.' The arrangement 1s such that when the bolt is so moved' as to bring: the handle 41 into's1ot40a the left hand swltch will be locked infopen position; in' the middle reoess 40 both switches" will' be locked in open position; and in 40 the right handiswitch will be locked-in open posi-tion.- The bolt must be' partially rotated so as to move the handle out ofsaid notches before' the bolt' cam be axially'movedto Io'ck the switches. In Fia'. 6 I halveshovvn the 1 bolt enolosingftube asihaving but'two notches 40 and 40 and the bolt is of such a length that it must always lock one and release the other switch.

Means are provided to lock said bolt 25 in any set position so that it cannot he moved from that position lo unlock or lock one of the other of the switches except by one having the proper key. Said means comprises the plate having the slot 51 thereA in ivhich is pivoted to a second plate 52 secured to the switch board 10.

The hook of a padlock is adapted tobe extended through said slot 51 to pass around and engage the handle 41 of said interlock bolt therebyI to positivelyY lock said bolt in any of the notches of said tube 23, when the padlock is unlocked and removed the plate 50 falls downward by gravity away rom said handle and the interlock bolt is thereby free to be moved.

In the modification shown in Fig. 8, the lock is applied to a single switch. In-this modification the tube 60 has aligned' apertures therethrou h and the bolt -G5 -has a hole therethroug which in the locked-op`en position of the switch is adapted to align with the apertures in said tube. A pin'GG is extended through the aligned apertures in'said tube and bolt andthe hook'of a-padlock 80 vis extended through a hole in-the end ovsaid pin'thereby to locki-the-pin against withdrawal whereby theswitchis positively loekedin o en position.

,It is obvious that ot er methods of lookin;r the switch an'dthe interlockmayV be einployedV Without departing from the spiritot' my invention.A

1. An electric switch havinga ymovable member formed with a locking aperture', a stationarymember, a locking-bolt movably carried thereby arranged' tofbe moved manu ally into and also out of the aperture in said movable member to lock'sa-id movable memheragfainstv or unlock itfor operation and means to lock said locking boltA against movement to said stationary member in both positiorisvof said locking holt.

2. An electric switclihaving a' face-plate, a switch-operatingrod associated therewith having a locking'member:` receiving-faperv ture,- said faoe-plate having an a'ertured lug, andia manually operable locklng bolt slidably received in the aperture of Asaid lug axra'nged to be moved manually into an also out of the aperture in said'operating rod to lock said rod against or unlock it `for operationfnd means to lock' said locking boltin rod-locked and also rodlunlockedpositions thereof. y

3. The combination of two switches having independent switchoperati 'mecha'- nisins; and manuell operablejloekingg,r means associated' 'with 'and manually movable' "independently of said mechanisms in oner d'- rection to engage and lock one of said mechanisms, and in the other direction to engage and lock the other mechanism.

4. The combination of two switches having independent switch-operating mechanisms, and manually operable locklng means associated with and manually movable independently of said mechanisms in one direction to engage and lock the first mechanism and release the second mechanism, and in the other direction to engage and lock the second mechanism and release the first mechanism.

5. The combination of two independently operable electric switches, manually-operable locking means movable independently of said switches into one position to lock one of said switches against operation and into an intermediate position to lock both switches against operation and into a third position to unlock the first switch and hold the second switch locked against operation.

6. The combination of two independently operable electric switches, manually-oper-` able locking means movable independently of said switches into one position to lock one of said switches against operation and into an intermediate position to lock both switches against operation and into a third position to unlock the first switch and hold the second switch locked against operation, and means to hold said manually operable means in set position.

7. The combination of two electric switches having independent switch-operating mechanisms, each mechanism having a bolt-receiving portion, a locking bolt extended between said mechanisms arranged for manual movement independently of said mechanisms to selectively lock said mechanisms against operation, and bolt-sup orting means in which said bolt is slidably received.

8. The combination of two electric switches having independent switch-operating mechanisms, each mechanism having a, bolt receiving portion, a locking bolt extended between said mechanisms manually movable independently of said mechanisms selectivelv to engage and lock one mechanism and disengage and unlock the other mechanism, and means to restrain said bolt in any set position.

9. The combination of two electric switches each having a face plate, an operating handle ivoted on each face plate, a switch operatmg rod connected with each handle extended through a slot in its face plate,

rod having a locking aperture therein, and

a locking bolt supported on said face plates each between said rods arranged to be moved manually independently of said operatmg rods into or outl of the apertures in said operating rods to lock said switches selectively in open condition.

10. The combination of two electric switches having independent switch-operating mechanisms, each mechanism having a bolt receiving portion, a tube extended between said mechanisms, supporting means therefor, a locking bolt slidably received in said tube manually movable into locking engagement with said mechanisms, said tube having a notched slot therein, and said bolt having a. knob removably received in said notches thereby to restrain said bolt in set position.

11. The combination of two electric switches having independent switch-operating mechanisms, each mechanism having a bolt-receiving portion, a tube extended between said mechanisms, supporting means therefor, a locking bolt slidably received in said tube manually movable into locking enlgagement with said mechanisms, said tube aving a notched slot therein, and said bolt having a knob removably received in said notches thereby to restrain said holt in any set position, and means to lock said bolt in set position.

12. An attachment for a pair of electric switches, each switch having a face-plate through which switch-operating mechanism extends, comprising a tube having supporting means at its ends engageable with the face plates for its support, a locking bolt slidably received in said tube manually movable into locking engagement with the switch mechanisms, said tube having a notched slot therein, and said bolt having a lmob removably received in one of the notches .whereby said bolt is restrained in set position.

13. An attachment for a pair of electric switches, each switch having a face-plate through which switch-operating mechanism extends, comprising a tube having supporting means at its ends engageable with the face-plates 'for its support, a locking bolt slidably received in said tube manually movable into locking engagement with the switch mechanisms, said tube having a notched slot therein, and said bolt having a knob received in one of the notches whereby it is restrained in set position, and a stationary member to which said knob is adapted to be locked.

In testimony whereof, I have signed my name to this specification.

HERBERT F. TURNER. 

